How to improve damage on my build? (LA Deadeye Ranger)

Your damage rolls on gloves, rings and weapon could be much better. Your +Skills rolls have a lot of room for improvement and your skill gems aren't even corrupted and leveled to 20+. That's where I would start.

1. Upgrade skill gems (at least your most used ones) to level 20. Uncut level 20 are about half a div each. Very good priced.
2. Upgrade your herald of thunder to a level 19. Uncut level 19 is about 1 div-ish.
3. Here are gloves that rolled much higher flat dmg for less than 10 divs:

https://www.pathofexile.com/trade2/search/poe2/Fate%20of%20the%20Vaal/D6j3bWB7t5

4. Here are some jewels to look at for less than 10 divs:

https://www.pathofexile.com/trade2/search/poe2/Fate%20of%20the%20Vaal/7ngbOVBBf5

5. Finish your 3 campaign permanent upgrades.

Not sure how much a +2/3 vertex is, but that would help. Rings, buy a decent ring & kalandras. On your tree try & spec to the 2nd quiver bonus, that will help. Also Ingenuity over HH. Hyrri armour also.